Problem

You are trying to save bookmarks, but Firefox seems to not be saving them or importing them.

Cause

The database that Firefox is using is corrupted and will need to be rebuilt.

The places.sqlite files need to be deleted so the database can be rebuilt.

Here is how you do it for the various OS...

For Linux

<random characters>.default

For Mac (Managed by ECI)

For Mac (Not ECI Managed)

Open up a terminal window by going to the upper right, clicking on the magnifying glass icon and typing 'terminal'
Type 'cd /Library/Application\ Support/Firefox/Profiles'
Type 'ls', you should see something like:

<random characters>.default

For Windows

Then start Firefox and check your bookmarks.